Magazine-conversion unit for firearms



June 23, y1953 M, M, JQHNSON'JR 2,642,688

msnm-CONVERSION UNIT PoR- FIREARMS Filed sec. e, 195o wlsneets-she'erlJune 23, 1953 11M. MfJoHNoN, JR: 2,642,688r

MAGAZINE-CONVERSION I mn F012.FIREARMS Filed Dec. e. 195o a V2sheets-sheet 2 Z? zg 30 1113128 zu 6 37 f/w H5 Patented `une 23, 1953UNITED STATES asias TENT OFFICE MAGAZINE-CONVERSION UNIT FOR FIREARMSApplication December 6, 1950, Serial No. 199,431

(Cl. A12- 50) 4 Claims.

The present invention relates in general to firearms of the box-magazinetype and more particularly to a box-magazine conversion-unit foradapting a box-magazine to a single-column cartridge-feed.

An object of the invention is to provide a superior conversion-unit forbox-magazines.

A further object of the invention is to provide a box-magazineconversion-unit of simple, durable and economical construction adaptedto be readily attached to and detached from the hinged floor plate of abox-magazine.

A still further object of the invention is to provide a box-magazineconversion-unit with fastening-means by which the conversion-unit may bereadily attached to or detached from the hinged floor plate of abox-magazine in the field without the use of tools or special equipment.

A still further object of the invention is to provide a box-magazineconversion-unit having fastening-means whereby the conversion-unit maybe readily attached to and detached from` the hinged floor plate of abox-magazine to adapt the latter to single-column cartridge-feed.

Other objects and advantages will appear to those skilled in the artfrom the following, considered in conjunction with the accompanyingdrawings.

In the accompanying drawings, in which certain modes of carrying out thepresent invention are shown for illustrative purposes:

Fig. 1 is a right-side elevation of a bolt-action rearm of thebox-magazine type with which the superior conversion-unit of theinvention is adapted to be used;

Fig. 2 is a fragmentary enlarged right-side elevation of the firearm ofFig. 1, partially broken away to show the action in its closed positionand the assembly of the conversion-unit on the hinged oor plate, thelatter being shown by broken lines in its unlatched position;

Fig. 3 is a transverse section of the rearm on line 3-3 of Fig. 2;

Fig. 4 is an enlarged fragmentary transverse section on line 4-4 of Fig.2;

Fig. 5 is an enlarged fragmentary right-side elevation of the firearm ofFig. 1 partly broken away to show the action open;

Fig. 6 is a transverse section on line 6-6 of Fig. I5

Fig. 7 is a right-side elevation of the improved box-magazineconversion-unit of this invention, with a portion of the lower side wallbroken away;

Fig. 8 is a bottom plan view of the conversionunit of Fig. '7 and Fig. 9is a top plan View of the hinged oor plate of the firearm to which theconversionunit is adapted to be attached.

For the purpose of describing the invention, the box-magazineconversion-unit is shown as used in the box-magazine of a bolt-actiontype of firearm. It will be appreciated, however, that 1 the particularfirearm illustrated herein is merely for the purpose of describing oneapplication of the invention and that the latter is applicable to otherfirearms of the type having a boxmagazine and a hinged iloor plate.

Referring especially to Fig. 2, the bolt-action rearm embodies, in themain, a receiver indicated generally at II) and having threadedlysecured to its forward end a barrel I3, the forward end of the receiverbeing provided with lockingshoulders I 4 for coaction with thelocking-lugs I5 on the forward end of an upturn-and-pullback breech-boltI6. The latter is adapted to reciprocate in the central bore I 'I of thereceiver which has a loading-and-ejection opening I8 in the top wallthereof intermediate its opposite ends. The locking-lugs I5 of the boltI6 are adapted to slide in guide-grooves of the receiver and to berotated through a quarter turn when the bolt is in its extreme forwardposition, as shown in Fig. 2, to coact with the locking-shoulders I4 ofthe receiver to lock the bolt in breech-closing position.

The receiver-and-barrel assembly is mounted on a solid stock I9 andsecured thereto by assembling-screws ZIJ, the stock being provided witha vertical box-magazine receiving-aperture 2I which extends therethroughfrom its top side to its bottom side and is substantially in alignmentwith the loading-and-ejection opening I8 of the receiver. The lower openend of the boxmagazine receiving-aperture 2| of the stock is adapted tobe closed by a floor plate 22. The latter is hinged at its forward endto the underside of the stock by means of a hinge-strap 23 which isseated in a recess in the underside of the stock and secured therein byone of the aforesaid assembling-screws 2U. The rear end of the hingedfloor plate is adapted to be engaged by a spring-loaded latch 24 whichserves to hold the oor plate in its normal closed position, as shown inFig. 2.

Mounted in the box-magazine receiving-aperture 2i of the stock is atop-loading box-magazine body comprising a substantially-rectangularsheet-metal sleeve-like member 25 having 3 side walls and end wallsarranged to engage securely against corresponding walls of theboxmagazine receiving-aperture 2|, as indicated in the drawings. Thebottom of the box-magazine body 25 is normally closed by the hinged oorplate 22.

The box-magazine is of the topp-leading type adaptedy to accommodate a"double` column of staggered cartridges for feeding the "cartridgessuccessively into the breech of the barrel form` chambering by thebreech-bolt, the feed-means' of the box-magazine body includingacartridge-v follower (not shown) and a follower-spring126. forsupporting and actuating the follower. The

lower end of the follower-'spring 2li is'i'adaptd" to be detachablysecured to"the"`hing"'e'd floor plate 22, and to this end the uppersurfacef"th"e' hinged floor plate 22 is providedfwitharelatively shallowsubstantially-rectangular recess 21 extending longitudinally thereof, asshown e"s"pec'il ally well in Fig. 9, and having a front end-wall 2'81"andfrear end-wall `2 9 i the *overl-"all i lerv'igtlfV of the recess 2 1being somewhat 'g'ater thaiiltlie' length-off-th'e lowermstea'f,Snf thefollowerspirg'.- Y l'The iwiith"v `f"the recess "21 correspondssubstantially to the width oftlieaforesaidleaf 3U 'ofthefllowerlspririg', wherebyfithe f lat'tefis afdapted toseatf'infthefrecess '2 Tfinfthef upper fcefofl-irie, hinged nominate:-#Fer-'deeper i 'the lowerleafft'efll.'off' the follower-'spring main,'"""sheetmetal bottom wall Y3ft' andtwoupf standinglaterallyespaced"sheet=metal"sidewalls 30W-#34,V forming" al holderfora* single' 'coluinn` oitca'rtridgesi vThe bottoni wallitof th'e'on-fiversioniuriitwis considerably narrowerLthanVf-thef box-magazine body25., as"shownespecially-well* in Figi -'6,' -and is provided' with-'f aseries-'ofsubstantially-rectangular Vapertures 35,733; 3l4 andgenerallybythe numeral 32 comprifsesfifrith' *ff 3 3` respectivelyspaced longitudinally tlfielere'go-f*asv 7,45"iness""fr"functi'onin'g`in the prescribedma Y.

i shown in Fig. 8, the width of the respective apertures 36, 31 and 38being substantially the same and slightly wider than the lower leaf 30of the follower-spring 26 as and for the purpose hereinafter described.The aperture 35 is relatively narrow as compared to the apertures 36, 31and 38 and is formed forl the purpose of providinlg a down-turned lip 33(fsee' Ei'g`.""7') which, as "s'hownespe'cially wellin' Fig. 5,`is"adapted to Y engage against the rear end wall 29 of the recess 21' inthe hinged floor plate 22 to positively hold the"conversion=unit 32against rearward displacement relative thereto when assembled thereon,as hereinafter described. Similarly, the

'aperture 'SSinitheforward end of the bottom wall 3 3 of theconversion-unit has a down-turned lip MVwhieli is"A adapted to engageagainst the frontmen'd "wal1r28jof the clearance-recess 21 of the hingedfloor plate to positively prevent the conversion-unit from movingforwardly relative to the iioor plate when"as sembled thereon. Theaforesaidaprture'36iand' the 'aperture 38 in the bottdm'wall of theconversion-'unit constitute cle'a aiicereces'sesfor accommodatingth'fc'ylinii driaf'erilarenients'of 'the' reverse" bends" of thelowermost leaf 3U and the next-succeeding upper leaf "4l" vof the'follower-spring a's illustrated: in Figs. 5`f"and 'j'soas`"toinsure'suii"icient-spacewithe in:4 vthe c"oni'/er'sio'n'''unit'lfor 'accommodating at l'asttliree ct'trtridges'l"`r 1""lfh'e'"afiiesaidAaperture 37 in the bottom wall 33 offtheconversibn-unit is providedfo''permiti ting the free"end"off'thedowermost l'efaf 3ll^`ofv theffollowerspring to project ltherethrough below f tueYVundersidefofrtnebpttem wants-brine `von: versioi'l-'imitfor detachableengagementin the IezeSsHZ'I Of'th'hged floor "plate,land;v in: par:ticiilai for'engagem'ent beneatli''tlie overhanging' upset-'3ith'ere'of;'in' themannershown especially well in Figs. 2 and 5.Referring:especially-'to Figs. 6 and '7, it will be seen that thelowerhalfk ofz'eachside wa'l1341 of f the *conversion-unit isbent outwardly,`-while the 'pper'half "of each side "wall isbe'n'tV inwardly; theber'id'at'the' juncture "of the' upper and' 'lower halves'of eacnside'`wall extendinglongitudinally ofthe conversion-'unit arranged'toengage'against the inner surface of thecorrespondingv iside#wallof"'th'e"`box=magazine 'body2 5 'when' the conver sion-unit isassembled therein. Each longitudiinalbend 42 thus'serves asfa'vfulcrum"for 'lateral displacement of tliieiipl'ier halves of the sidewalls 34-34of the conversion-unit when loading car-I tridges into theA top'ther'eoflin the 'manner characteristic'bf magazinesfoff-the top-loading type.iAs" shownl esr' 'ecially"wellA Fig'. '7 the`- upper half of each sidewall 34 of the'conversionunit is "provided iwith a"substantially-verticalf slot" d3 intermediate its'opposite ends', whichIdivides the upper "'half 'of 'each""respe'ctive side wall into arear"portion and frntpotion," the rear 'portions ofthe sidewallsoffthe*'conversionunit being symmetrical with` respect to theVerticalaxis' of' the conversioniunittand inclined 'inwardly so'that thetransverse distance betw'eeen'" the upper angededges 4'4-44 1 of: therear portions of the side walls 34-34 is slightly'less'thanitliediameterof a' cartridge. r`TheV` upper Aflaifiged'edgesY Mii-"T114 of thelconifersion-uit thus serve resilient' lips for holding thecartridgesintheonversionunit f down Yagair'ist theupwardly'direote'd'force' of the The upper edges 45-45 of the forward portions of the sidewalls 34--34 of the conversionunit are preferably cut down, as indicatedespecially well in Fig. 7, so as to increase the lateral spacing of theupper edges thereof so that these upper edges of the conversion-unitwill permit a cartridge to pass upwardly freely therebetween wherebycartridges may be elevated by the follower and follower-spring assemblyof the conversion-unit into position for chambering by the breech-bolt,as hereinafter described. In this connection, the follower 46 of theconversion-unit comprises a strip of relatively-stiff sheet-metal stock,the opposite longitudinal edges of which are turned under, as shownespecially well in Fig. 6, to provide stiffeningmeans, the followerhaving preferably a slight convex curvature in cross section. Theturnedunder edges of the follower also include a pair ofinwardly-projecting spring-retaining `lips 41-41 with which the free endof the uppermost leaf 48 of the follower-spring is adapted to be engagedfor detachably securing the follower thereto.

Inasmuch as each side wall of the box-magazine body 25 is providedadjacent its forward end with an inwardly-struck substantially-verticalcartridge-guide rib, each side wall 34 of the conversion-unit isprovided in its forward portion with a clearance-aperture 49 foraccommodating the cartridge-guide ribs of the box-magazine body when theconversion-unit is assembled therein.

As shown in Fig. 6, the maximum internal width of the conversion-unit isless than the Width of the box-magazine body 25. Moreover, the upperhalf of each side wall of the conversion-unit is inclined inwardly, ashereinabove described, so that the resilient lips 44--44 of theconversion-unit will be spaced apart less than the diameter of acartridge. Consequently, the conversion-unit holds one less cartridgethan a double-column-feed type of box-magazine, the cartridges beingarranged in the conversion-unit in a semi-staggered relationship withthe uppermost cartridge held by the resilient lips 44--44 substantiallyin axial alignment with the bore of the barrel for achievingsingle-column feeding.

The operation of the conversion-unit of the firearm is as follows: Letit be assumed that the shooter wishes to convert the double-columncartridge-feed. type of box-magazine in the rearm to single-columncartridge-feed so as to prevent malfunctioning of the firearm when usingsoft-nosed bullets. The shooter unlatches the hinged floor plate 22 ofthe box-magazine and allows it to swing downwardly into asubstantially-vertical position, whereupon he disengages the leaf 3D ofthe follower-spring from the spring-retaining lips of the floor plate.He thereupon disengages the double-column-feed type of follower from theupper leaf 48 of the spring 26 and attaches to the latter the sheetmetalfollower 46 of the conversion-unit 32. He then slips thesingle-column-feed follower 46 and the follower-spring 26 between theside walls 34--34 of the conversion-unit with the lower leaf 30 of thefollower-spring projecting through the aperture 31 in the bottom wall 33of the conversion-unit. The completely-assembled conversion-unit is thenmounted on the hinged floor plate 22 by engaging the free end of thelower leaf 30 of the follower-spring beneath the springretaining lips3l-3l of the floor plate, whereby the conversion-unit 'is detachablysecured thereon, the unit being positively held against movementlongitudinally relative thereto by engagement of the respective lips 39and 40 with the corresponding end Walls of the recess 21 in the floorplate. The shooter then swings the hinged floor plate up into its normallatched position thereby moving the conversion-unit up into thebox-magazine body 25. The firearm is now converted for single-columncartridge-feed so that cartridges held in the conversion-unit of theboxmagazine will be fed therefrom in substantiallyaxial alignment withthe bore of the barrel.

Assuming cartridges have been loaded through the top of theconversion-unit, then upon moving the breech-bolt forwardly from itsrearmost position, the forward face of the bolt will engage the upperedge of the uppermost cartridge in the conversion-unit of the magazinein the manner shown in Fig. 5, and advance the uppermost cartridgeforwardly therein whereby the nose of the cartridge is brought intoengagement with the mouth of the breech and is guided upwardly by thesloping surface thereof into the bore of the barrel. When the bolt hasadvanced sufficiently to bring the rim of the cartridge opposite thevertical slots 43-43 in the walls 34-34 of the conversion-unit, thecartridge is released from the resilient cartridge hold-down lips 44-44of the conversion-unit and is thereupon moved upwardly by the force ofthe compressed follower-spring into engagement with the extractor on theface of the bolt, the upward and forward movement of the cartridge beingconcurrent with the forward movement of the breech-bolt, whereby thecartridge is chambered in the bore of the barrel. The bolt-operatinghandle is then swung down to engage the locking-lugs I5 of the bolt withthe locking-shoulders I4 of the barrel for locking the bolt inbreech-closing position preparatory to ring the piece. After firing thecartridge in the barrel, the action is opened by the upswing andpullback of the bolt-handle, whereupon the fired cartridge is extractedfrom the barrel by the rearward movement of the breech bolt and pulledrearwardly opposite the loading-and ejection opening I8 of the receiver,from which the fired cartridge is ejected in the usual manner. At theend of the rearward excursion of the breech-bolt, the next-succeedingcartridge in the conversion-unit of the magazine is moved upwardly bythe follower and follower-spring assembly to project into the path ofthe front face of the breech-bolt, in which position it is resilientlyheld by the hold-down lips 44-44 of `the conversion-unit. The firearm isagain ready for loading a new cartridge into the chamber of the barrel.

The invention may be carried out in other specific ways than thoseherein set forth without departing from the spirit and essentialcharacteristics of the invention, and the present embodiments are,therefore, to be considered in all respects as illustrative and notrestrictive, and all changes coming within the meaning and equivalencyrange of the appended claims are intended to be embraced therein.

I claim:

1. In a box-magazine firearm, the combination with a box-magazine bodyof the doublecolumn cartridge-feed type having a hinged floor plate forclosing the lower end of said box-magazine body: of a conversion-unitfitting snugly within said box-magazine body for converting said .$99111'.bneureleaay anehered to. said-hinged $1991@ ,91am eed; releaeablyinterlecnee with.. said @Qrlvesien 1111.119 fer detaelzlable abtachmeml9i-.bhe

b9 Said. fleer plate.,

a.. bex-magazine nr-earm .1., Wheein sacl- 119er: plat-.eY is nleYded.with. a. reess and snrinewetainmgflips eesiienegl; on genesis-.e sidesofsaid recess whieh DQjGnWaxdly eWardS.. eeen other` to.. oyerle the bettm. er. sai@4 recess, one end ofsow`r folV mg being detahably anchqged tosaid o e 121,843.6 'Sliding' engagement under said .9,..-rlv-l6i 19gHRS; to. fratonally. hold; that epd O.`f,saigil follewerespring. againstthe bottom ofthe recess Qffsaid, 1.10.01? plate.

3. .'-Ijhee @Qmbinaton in a bex=magazine rearm as.; Qned in. elaim 2,vszhereinV sadconversion unit epmpses. a. lcnagafagme having-abottomowall ang: gpstandng. side walls connected wsad hot-JA tem Wall;said. bettom .wellbeing aperturedfand Solid' free end ofy saidfollowerespringprojecting therethrough for engagement with saidspringretail-gne lips.

4e Ina'rearm. oi the converted. box-magazine type, .the combinationwith. a.A m0untedbox-maga Zine of ,the deuble-.eolumn cartridgeffeedtype, a ,hngedveox plate to..c1ose. the bottom of .said magazine. and a..cartridge follower spring releasablyqlanhered. .teisaidz floer. plate,of a carbridge helderinsertable insana` magazine for con- Yertng Lthelatter tQ..s ing1e.-co1umn. cartridge-feed, said` cambridge, holder:being releasably` nterlocked with :saidileor plate. and said.springendheld by thezlatterf in interlock with said oor platev to loe,l carriedthereby immy and from; said magazine.

' MELVIN M JOHNSON, JR.

.Reienencee Qited inthe-file ofmhis. paemv UNITED STATES PATENTS NumberName. Date.

.5218.69 .Mauser oet. 23,J 18.94 1,306,912. Jbelson -M June. 175, 1919145,512,457.. Sept. 8,1925 1.999,61!) Feb.. 21, 1.93.3 .ZofiflszaHarvey. Jan. 19,v 1948

